Method and devices for regulating the flow rate and for slowing down non-ferromagnetic, electrically-conducting liquids and melts

Abstract

The invention relates to a method for regulating the flow rate and for slowing down non-ferromagnetic, electrically conducting liquids and melt streams through magnetic fields, in particular in the tapping of metallurgical containers such as blast furnaces and melt furnaces. The method is characterized in that the melt stream is routed in a closed routing element using at least one stationary magnetic field with a constant polarity, at least one stationary magnetic alternating field or using a multi-poled magnetic travelling field, in such a way that the magnetic field lines transversally penetrate the melt flow across the entire cross section thereof and such that a voltage is induced in the melt stream by the magnetic fields, there being eddy currents induced thereby in the melt stream that are disposed radially and axially when a stationary magnetic field of constant polarity is used and that are disposed axially when a stationary alternating magnetic field or electromagnetic travelling field is used, and that due to the interactions between the magnetic fields and the eddy currents forces are generated that can affect the flow rate of the melt stream.

The invention claimed is: 
     
       1. A method for regulating the flow rate and for decelerating non-ferromagnetic, electrically conductive liquids and melts using electric magnetic fields while said liquids and melts flow through a guide element when tapping metallurgical containers, said method comprising:
 guiding a stream of liquid or melt in a flow direction in a closed guide element through at least one stationary magnetic field with constant polarity, said guide element being a conduit pipe of an electrically conductive material, wherein magnetic field lines transversely penetrate the stream over its entire cross section, in that voltages, the level of which is proportional to a local flow rate of the stream and a local strength of the magnetic field, are induced within the magnetic field perpendicular to the magnetic field lines, in that the voltages generate electric eddy currents that are directed radially and axially relative to the flow direction of the stream and have an intensity that locally differs over the flow cross section of the stream, wherein forces of locally differing intensity that influence the flow rate of the stream are generated due to interaction between the magnetic field and the eddy currents, and in that a flow profile of the stream is homogenized and decelerated as the magnetic field strength increases. 
 
     
     
       2. The method according to  claim 1 , in which the stream is guided through a guide element of electrically conductive material in order to prevent an electric resistance and a resulting amplification of the eddy currents with correspondingly amplified deceleration force. 
     
     
       3. The method according to  claim 2 , in which the guide element is cooled in order to form a protective layer of solidified melt on the inner wall as a protection against wear. 
     
     
       4. A method for regulating the flow rate and for decelerating non-ferromagnetic, electrically conductive liquids and melts using electric magnetic fields while said liquids and melts flow through a guide element when tapping metallurgical containers, said method comprising:
 guiding a stream of a liquid or melt in a closed guide element through one of a stationary alternating magnetic field and a multipolar traveling electromagnetic field such that magnetic field lines transversely penetrate the stream over its entire cross section and a voltage is induced in the stream and generating axial eddy currents in the stream, and in that forces generated due to the interaction between the magnetic field and the eddy currents are able to lower and accelerate a flow rate of the stream and to stop the stream, wherein said guide element being a conduit pipe of an electrically conductive material. 
 
     
     
       5. The method according to  claim 1 , in which the greatest forces acting upon the stream are generated in a region of the stream with the highest flow rate. 
     
     
       6. The method according to  claim 4 , in which a variation of the supply frequency of the three-phase current for operating the induction coils in order to generate a traveling magnetic field and a variation of the speed of the traveling magnetic fields caused by the frequency variation of the three-phase current in order to influence the eddy currents generated in the stream and the forces acting upon the stream. 
     
     
       7. The method according to  claim 1 , in which a force directed opposite to the flow direction of the stream is generated due to the interaction of the magnetic field or the magnetic fields with constant polarity with the eddy currents, wherein said force lowers the flow rate of the stream and simultaneously reduces the turbulences. 
     
     
       8. The method according to  claim 4 , in which a force directed opposite to the flow direction of the stream is generated due to the interaction of the alternating magnetic field or alternating magnetic fields and of the traveling magnetic field or traveling magnetic fields with the eddy currents, wherein said force is able to lower the flow rate of the stream, to stop the stream and to reverse the flow direction of the stream. 
     
     
       9. The method according to  claim 1 , in which a variation of the magnetic field or the magnetic fields increases or decreases the forces acting upon the stream. 
     
     
       10. The method according to  claim 9 , in which the frequency of the alternating field and of the traveling magnetic field and the frequency of the electric current generating the alternating field and the traveling magnetic field are variable and can be adapted to different circumstances. 
     
     
       11. The method according to  claim 1 , in which the magnetic flux of the magnetic field acts upon the stream in a decelerating fashion opposite to the flow direction thereof in a closed magnetic circuit when the stream enters the magnetic field and when the stream exits the magnetic field of the magnetic circuit. 
     
     
       12. The method according to  claim 1 , in which a series connection of at least two closed magnetic fields with constant polarity and by a double utilization of the magnetic flux of the magnetic fields and the double utilization of the eddy currents in order to increase the deceleration effect exerted upon the stream. 
     
     
       13. The method according to  claim 1 , in which the stream includes liquid metal and slag, and utilization of different effects of the magnetic field on the liquid metal and on the slag in the stream separates the liquid metal and slag of the stream. 
     
     
       14. The method according to  claim 4 , in which a variation of the magnetic field or the magnetic fields is made in order to increase or decrease the forces acting upon the stream. 
     
     
       15. The method according to  claim 4 , in which the magnetic flux of the magnetic field acts upon the stream in a decelerating fashion opposite to the flow direction thereof in a closed magnetic circuit when the stream enters the magnetic field and when the stream exits the magnetic field of the magnetic circuit. 
     
     
       16. The method according to  claim 4 , in which the stream includes liquid metal and slag, and utilization of different effects of the magnetic field on the liquid metal and on the slag in the stream separates these liquid metal and slag of the stream.